Mechanical linkage joint



Sept. 27, 1966 v. L. PEICKH ETAL MECHANICAL LINKAGE JOINT Original FiledDec. 9,- 1963' 5 Sheets-Sheet 1 P 27, 1966 v. 1.. PEICKII ETAL 3,275,352

MECHANICAL LINKAGE JOINT 5 Sheets-Sheet 2 Original Filed Dec. 9, 1963Fig 5 Fig. 7

LHHEHHH- p 27, 1955 v. L. PElCKlI ETAL 3,275,352

MECHANICAL LINKAGE JOINT Original Filed Dec. 9, 1963 5 Sheets-Sheet 5the steering wheel rim force.

United States Patent 3,275,352 MECHANICAL LINKAGE JOINT Vasalie L.Peickii, Hillsborough, Dan A. Christensen, Woodside, and John H.Bradfute, Santa Clara, Calif., assignors to Federal-Mogul Corporation, acorporation of Michigan Original application Dec. 9, 1963, Ser. No.330,518, now Patent No. 3,233,928, dated Feb. 8, 1966. Divided and thisapplication Aug. 10, 1964, Ser. No. 401,746

12 Claims. (Cl. 28785) This invention relates to a mechanical linkagejoint of the type which has two pieces that swing relatively to eachother. This application is a division of application Serial No. 330,518,filed December 9, 1963 and now Patent No. 3,233,928, which was acontinuation-in-part of application Serial No. 189,613, filed April 23,1962 and now abandoned.

In contrast to the types of ball joints and hinges in which metalmembers directly engage each other and rotate relatively to each other,the present invention relates to a novel type of linkage in which a pairof metal members are joined together by an elastomeric connector whichis bonded to 'both of the members. Typical types of assemblies where theinvention may be used include steering gear links, universal joints,wheel suspensions, shock absorber arms, and many other places where balljoints and hinges have been used.

Considering as an example the use of the invention in automativesteering rod linkages, it is known that each steering linkage system forthe front wheels of an automobile requires several ball joints and thatsuch joints are relatively expensive and usually require maintenancelubrication. The present invention makes it possible to provide a muchless expensive type of linkage at each joint with even superior results.Thus, one object of the invention is to provide a simpler and morereliable connection which has no maintenance requirements over a longuseful life.

The joint of this invention has substantially all of the advantages of aball joint but in addition it is simpler, requires no maintenance, dampsshock and vibration, and so transfers less of them from one rod toanother, and is free from the possibility of wear which results fromsliding contact. In many applications the joint of this invention has amuch longer life than joints heretofore in use. Furthermore, the jointis fail-safe in that if the elastomer should fail completely,-theinterlocking metal members couldstill not come apart.

When used in a steering linkage, the invention provides flex joints thatreduce the road and front wheel noise and vibration transmitted throughthe steering linkage, giving a quieter ride and a more solid soundingcar. The joints have an inherent centering force and lack of friction,enabling alteration of the front-end geometry so as to lower Since thejoints have no clearance between their moving parts, they have no freeplay at any time, in contrast to conventional joints in which the freeplay increases with wear; the joints-of this invention have no wearingsurfaces and remain tight during their entire service life.

Moreover, shock loads such as are caused when a front wheel drops in achuck hole in a road have heretofore been transmitted to the steeringgear box undiminished by a conventional linkage; whereas, in the presentinvention, the shock is dampened by each joint, and each joint throughwhich the shock passesreduces the severity of the shock.

In the joint of this invention there are no wearing surfaces, so thatthe joint life can be made to equal the car ICC life. No lubrication isneeded, and maintenance is eliminated. Moreover, not .only are thejoints in themselves less expensive than conventional joints, but due totheir lasting as long as the car, it is not necessary to makeconcessions to ease of replacement of them, and the tie rod joints canbe made integral with the steering arm, for example.

When the joint of this invention is used in other applications similaradvantages are obtained, as well as additional ones specific to theparticular application.

Other objects and advantages of the invention will appear from thefollowing description of some embodiments thereof.

In the drawings:

FIG. 1 is a plan view of a portion of an automobile steering linkageemploying joints embodying the principles of the present invention.

FIG. 2 is a diagrammatic plan view showing a steering linkage like thatof FIG. 1 when a right turn is being made by the vehicle.

FIG- 3 is a view similar to FIG. 2 showing the position of the elementsin the linkage when a'left turn is being made by the vehicle.

FIG. 4 is a fragmentary view in section, taken along the line 4-4 inFIG. 1.

FIG. 5 is an enlarged view in section of a flex joint embodying theprinciples of the invention.

FIG. 6 is a view in perspective of a modified form of joint embodyingthe principles of the invention, with a portion cut away and shown insection and With the clastomer omitted.

FIG. 7 is a view inplan and in section taken along the line 77 in FIG.6, with the elastomer shown.

FIG. 8 is a view similar to FIG. 7 showing the joint in a differentrotational position. I

FIG. 9 is a view in section taken along the line 9--9 in FIG. 7.

FIG. l0.is a view similar to FIG. 9 showing the joint in an extremeangularly flexed position.

FIG. 11 is a view similar to FIG. 9 of a slightly modified form of theinvention generally similar to that of FIG. 9.

In order to illustrate the utility of the invention and to give someidea of its purpose and -function, FIGS. 1 to 4 show a portion of thesteering linkage at the front end of an automobile. Thus, the linkage 20transmits the turning from a steering wheel 21 to front wheels 22 and23. A rod 24 connects the steering wheel '21 to a gear box 25 from whicha rod 26 passes to a joint 27 of the present invention. From the joint27, a rod 28 extends across tothe opposite side of the automobile to asimilar joint 29, whence a clevised rod 30 is connected to a pair ofsuch joints 31 and 32, and rods 33'and 34 lead from the joints 31 and 32to a frame 35. The gear box 25 is bolted to the frame 35. Near itscenter, the rod 28 is connected to short rod members '36 and 37 that arerespectively joined to joints 38 and 39 of this invention; the joints 38and 39 are connected by respective rods 40 and 41 to joints 42 and 43,which in turn are connected by rods 44 and 45 to members 46 and 47 thatsupport spindles 48 and 49 for the wheels 22 and 23. Each one of thejoints 27,29, 31, 32, 38, 39, 42, and 43 is shown as one that embodiesthe present invention. -It will be noted that the two rods which lead toor from any joint may take various positions as shown by FIGS. 2 and 3and may or may not lie in the same plane.

Each joint 27, 29, 31, 32, 38, 39, 42 and 43 may be constructed like thejoint of FIGS. 6-11, orlike the joint 60 of FIG. 5. The joint 60 of FIG.5 has two loops or eyes 61, 62 each forming the end of a metal rod 63,64 or having a stem which is threaded to the end of a rod, either in theplane of the loop or not. One loop 61 may be a completely closed circleforged for that purpose, while the other loop 62 may be inserted andclosed around it and may be closed completely by welding, or may be leftwith the looped end of the rod flush against thestem. In either.instance, the device is fail-safe, due to the interlocking of the twoloops 61and 62.

The two stems 63, 64 or 71, 72 may be held in any relative positiondesired during molding. For convenience, the drawings show them held inthe position where they are perpendicular to each other, but they couldbe held at an angle and molded at rest in that position, or they may bemolded perpendicular and the joint stressed to that position, whichevergives the most desirable results for a particular instance. Theadaptability of the invention in this particular is quite great,enabling the rest position to be determined at the time of molding. Theoption of stressing the joints on assembly allows the engineer designinga linkage system to vary the turning force of the steering wheel at anyposition of the linkage.

An elastomer is used to fill the joint. In FIG. 5 the elastomer member65 is one integral member bonded to both loops 61 and 62 and has twoplanar portions, as shown in FIG. 1, that lie along the plane ofrespective eyes 61, 62 filling both eyes 61 and 62 and joining each eyeto its adjacent eye. Thus, the member 60 is shaped generally like twointersecting discs filling the space enclosed by the eyes 61 and 62 andalso covering and bonded to the metal of the eyes61, 62..

Any elastomer suitable for the use involved is satisfactory, thenecessary strength and flexibility being provided by proper choice ofpolymer and by compounding procedures well known in the art.

When one rod 63 is moved relatively to the other rod 64 to flex thejoints, the elastomer. is deformed, setting up stresses as it moves intothe shape shown. Thus, the one loop 62 moves closer. to the other loop61 during the turn with a force tending to return it to the originalposition, both by the tensile force and the compressive force exerted onthe el-astomer 65..

Thus, the action of the joint of this invention is differ ent than'thatof a normal hinge or a metal joint of this type in that there is nostresslesspivoting, but instead, the

members are turned in a way which sets up stress. They are held togetherwithout having to be concernedwith fits, finish, lubrication and so on,all these being taken care ofby the. inherent properties of theelastomer 65.

An important feature of the invention is the fact that the loops canrotate about the center of the joint against relatively lightforce inthe elastomer, but the loops are restrained from relative translation byconsiderably greater elastomeric force. The reason is that elastomershave a much lower shear modulus than tensile modulus for any givenelongation. In other words, the elastomer is soft in shear but still intension and compression. This.

helps to retain proper alignment during operation.

In any particular installation, one loop of the double- =1oop joint isloaded torsionally and the other loop is loaded as a diaphragm. Sincethe diaphragm has essentially tensile loading, it is possible to removecertain portions of the elastomer from the diaphragm loop andthereby toreduce the rotary stiffness of the joint by a substantial amount. It issometimes advisable to remove a portion of the elastomer or to so moldit that it is not present in order to reduce some of theeffects noted inthe form of the invention previously described. Thus, in the joint 60,openings 69 extend through the body 65 along the axis of the rod 63 onboth sides, of the eye 61. The openings 69 are diametrically oppositeand are symmetrical to a'diameter that lies perpendicular to theaxis ofthe rod 64.

These openings reduce the force required to rotate the rods 63 and 64about the center of the joint 60 While pin or stud may be substitutedfor the loop 61 of FIG, 5

with little or no impairment of its function. This results in the joint70, where two rods, 71 and 72, are poined together by an elastomericbody 73. The rod 71 is provided with a widened end portion 74 having aring 75 which may be substantially longer along its axis76 than thethickness of the rod 71, and which may have a gen erally rectangularcross-section allowing for curves needed for forging, relieved endportions 77 and 78 being preferably provided to enable a greater turningradius, as shown in FIG. 10.

The rod 72 has an end ring 79 to which is secured a stud 80, providingan end portion preferably perpendicular to the rod72. Prefenably, atapered end portion 81 of the stud is driven into a tapered opening'82.in the ring 79 and locked there by a nut 83. If desired, the. stud maybe an integral bent over portion of the rod 72. The stud 80 may begenerally cylindrical or may have another shape, and it may beconsidered as a pivot pin movable inside the ring 75, (an externalanchor for the elastomer). The end portion or stud 80 extends all theway through the ring 75 and is provided at its opter end with afail-safe or locking device which may simply be 85 and 86 extend all theway through thebody 73 in or-.

der to make it easier to get rid of dirt, but the function is notgreatly affected .by a partial filling with a thin web. These openingsare arranged to lie; generally diametrically opposite each other at theside .With respect to the rod 71 rather than in line with the rod 71;that is, they do not.

lie within the area represented by an extension of the rod 7 71 throughthe end portion or along the actual loading Thus, the elastomerfillsxthe spaces axis for the joint. 87 and 88 between the stud 80 andthe ring 75 that are axially in line with the rod 71, while the reminderof i the space between the ring 75 and stud 80 may be vacant or may bepartially filled. In effect, the portions 87 land 88 1 act as blocks ofelastomer whichare diametrically opposite, are axially aligned, are ofequal size andare spaced apart (by the openings85 and 86).. The openings85 and 86 may be arcuate as shown,.or they may bean.

other shape. a.

The structure of claims 6-10 enables. an increasein the joint bearingarea, which in FIG. 5 is approximately a square with its sides. equal tothe diameters. of the'rods 63 and 64 and their. loops 61 and 62 whicharelinked In the case of the joint 70, the bearing area has *beenincreased, increasing the height of the ring 75.

together.

and its elastomeric filling 76; that is, the distance the ring 75extends parallel -to the stud 80 or the amount that-the elastomericfilling 73. extends within the ring..75 and along the axial direction ofthe end portion 80. This structure eliminates the diaphragm loop ofrubber and with it certain forcecharacteristics which, for manyinstallations such as certain automative tie rod ends, are

undesirable. Automotive tie rod joints achieve theirbest results whenthere is minimum deflection under highaxial V loads and minimumtorsionalstiilness, especially in the higher deflection range. Therubber volumes (the blocks 87 and 88) lying along the axis of the rod 71are, respectively, under tension and compression with axial loading,which is under tension and which is under-compression depending onwhether therod 71 is being pulled or whether it is pushed. The rubber atthe sides (where thecholes-85and 86 are) is'loaded in shear, and since,as has been pointed out before, this is essentially less efiicient, thestructure of FIGS. 6 to 10gives ideal results, with the stud 80 lyingalong the center line 76 of the loop 75, and the rubber'blocks 87 and-88connecting them along the axis of the attaching rod-70 for the loop 75,the blocks 87 and 88 being as Wide as the stud 80 and as high as thering 75. (The rods 70 and v71may be offset or curved; what is importantis the loading axis.)

The structure of FIG. 11 illustrates a modification of the device OtfFIGS."6 through 10 wherein the ring 75a is tilted with respect to therod 71. This is perfectly feasible and for some uses may given improvedresults. The tilting may be in difierent angles, but it will be notedthat the end portion or stud 80 is centered with respect to the axialline 89 of the rod 71 and is also centered in the ring 75a. Note thatthe ring 75a is centered with respect to the axial line 89, so thatthere will be the same amount of elastomer above as below the line 89.

It will be appreciated that in some instances the failsafe precautionsare not needed. Not only can the member 84 be eliminated; the ring 75does not need to extend full circle or even be a ring so long asrigidity is provided by an anchor on both sides of the blocks 87 and 88.What appear here as openings 85 and 86 because of covering of the fullperiphery of the stud 80 and of the inner periphery of the ring 75, maybe gaps or omissions, the blocks 87 and 88 being suificient for manypurposes.

To those skilled in the art to which this invention relates, manyadditional changes in construction and widely differing embodiments atthe invention will suggest themselves without departing from the spiritand scope of the invention as defined in the claims.

What is claimed is:

'1. A steering joint comprising a pair of rod means lying inapproximately parallel planes and at least one of which has a loop onone end, the loop having an axis, the other said rod means having an endportion extending into said loop along the axis of the loop and havingmeans interlocking said end portion with said loop and preventingretraction from said loop, and an elastomeric connecting means withinsaid loop and molded and bonded to both said loop and said end portion,said connection including two substantially diametrically oppositeloading portions spaced by apertures defining voids, the said rod havingsaid loop extending along the diametric axis of said loading portions,whereby said rod means can rotate about said joint against relativelylight force in the elastomer due to said voids, said rod means beingrestrained by said loading portions from translation of the two rodmeans relative to each other by considerably greater elastomeric force,whereby a longitudinal force along the axis of the said rod means havingsaid loop, tends to produce tension in said elastomeric connecting meanson one side of said end portion and compression in said connecting meanson the other side of said end portion and translation of such steeringjoint, which in turn act to cause relative rotation of the other saidrod means in a plane approximately parallel to that of the [first namedrod means with resultant rotation of said end portion relative to theaxis of said loop, whereby torsion is set up in said elastomericconnecting means along the plane of said loop, the level of torsionalforce being a fraction of what would be present in a solid saidelastomeric connect-ing means because of said voids.

2. A steering joint between first and second relatively rotatable rodseach having its own longitudinal axis, comprising a ring on the end ofsaid first rod and generally axially in line therewith, said ring havingan axis of its own, ,an end fitting on said second rod extendingperpendicularly to the axis of said second rod and passing centrally andaxially through .said ring and having a terminal memberon its endpreventingretraction of said end fitting out of said rin and a generallycylindrical elastomeric body bonded to and joining both said iing andsaid end fitting and substantially filling the space axially in linewith the axis of saidfirst rod and on both sides of saidend fittingbetween saidring and said end fitting, said body having throughopeningsparallel to' said end fitting on both .sides thereof anddiametrically opposite one another outside of the space axially in linewith the axis of said first rod, whereby a longitudinal torce along theaxis of said firstrod produces tension in the said elastomeric body onone side of said end fitting and compression in said body on the otherside of said end fitting and translation of said steeringjoint, which inturn acts to cause relative rotation of said second rod in a planeapproxim-ately parallelto thatof said first rod, with resultant rotationof said end fitting relative to the axis of said ring, whereby torsionis set up in said body along the plane of said ring, the level oftorsional force being a traction of what it would be in a solid saidbody, because of said through openings.

3. The steering joint of claim 2 wherein said ring is circular and saidopenings are arcuate along arcs generally concentric with said ring.

4. The steering joint of claim 2 wherein the plane of said ring and bodyis tilted relative to the plane of said first rod.

5. A steering joint structure, including in combination a pivot pin, apair of diametrically opposite, axially aligned, equal-size,spaced-apart elastomeric blocks bonded to said pivot pin, an externalanchor having portions lying on diametrically opposite sides of said pinand bonded to the extreme opposite ends of said blocks, said pin beingcentered relative to said anchor, rod means secured to said pivot pin,and loading means secured to said anchor along the diametric axis ofsaid blocks for applying load to said pin through compressive-tensileloading of said blocks along the axis of said blocks, whereby said pinand rod rotate relative to said anchor and said loading means atrelatively light torsional stress over a substantial angle and translatewith said anchor and loading means.

6. A steering joint structure, comprising a straight pivot pin, a pairof diametrically opposite, axially aligned, equal-size, spaced-apartelastomeric blocks bonded to opposite sides of said pivot pin, anexternal anchor having portions lying equidistant from and on oppositesides of said pin and bonded to and confining the extreme opposite endsof said blocks and axially in line with them, a first rod secured .toone end of said pivot pin, and a loading rod secured to said anchoralong the diametric axis of said blocks for applying load to said pinand said first rod through compressive-tensile loading of said blocksalong the axis of said blocks, whereby said pin and said first rodrotate relatively to said anchor and said loading rod at relativelylight torsional stress over a substantial angle and translate with saidanchor and loading rod.

7. The steering joint of claim 6 wherein said anchor is a ring andwherein said loading rod is axially in line with said blocks, saidblocks being spaced apart by voids between said n'ng and pin.

"8. The steering joint of claim 7 wherein there is a projection on theother end of said pivot pin positively preventing said pin from beingtaken out of said ring, even were said blocks to be absent.

9. A steering joint comprising a pair of rods, the first of which has aloop on one end, the second said rod having a terminal stud at one endperpendicular to said second rod and extending into said loop along theaxis of the loop, and an elastomeric connecting means within said loopinterposed between and molded and bonded to both said loop and saidstud, said connection including diametrically opposite loading portionsspaced apart by diametrically opposite apertures defining voids, thesaid rod having said loop extending along the diametric axis of saidloading portions, whereby said rods can rotate about said joint againstrelatively light force in the elastomeric connecting means but arerestrained irom translation of the two rods relative to each other byconsiderably greater elastomeric force. a

'10. The steering joint of claim 9 having fail-safe means on theopposite end of the stud from said second rod preventing retraction ofsaid stud from ,said loop.

11. The steering joint of claim 9 wherein said loop has a generallyrectangular cross-section and is axially longer along the axis of saidstud than the height of said first rod.

12. The steering joint of claim 11 wherein the voids in said elastomericconnecting means comprises openings extending axially of said loop allthe way through said connecting means and are centered along -a diameterperpendicular to axis of said first rod.

References Cited by the Examiner UNITED STATES PATENTS 7 1,867,540 I7/1932, Rosenberg 6411 X 2,273,869 2/1942 Julien. 2,324,984 7/1943Brown. 2,367,033 1/1945 Lear 287 -85 2,958,526 11/1960 Ulderup et al.26763 FOREIGN PATENTS 609,437 2/ 1935 Germany.

483,530 4/ 1938 Great Britain.

811,668 4/ 1959 Great Britain.

OTHER REFERENCES Voigt: German application 1,039,314, printed Sept. 18,1958.

CARL W. TOMLIN, Primary Examiner.

A. V. KUNDRAT, Assistant Examingn;

1. A STEERING JOINT COMPRISING A PAIR OF ROD MEANS LYING INAPPROXIMATELY PARALLEL PLANES AND AT LEAST ONE OF WHICH HAS A LOOP ONONE END, THE LOOP HAVING AN AXIS, THE OTHER SAID ROD MEANS HAVING AN ENDPORTION EXTENDING INTO SAID LOOP ALONG THE AXIS OF THE LOOP AND HAVINGMEANS INTERLOCKING SAID END PORTION WITH SAID LOOP AND PRVENTINGRETRACTION FROM SAID LOOP, AND AN ELASTOMERIC CONNECTING MEANS WITHINSAID LOOP AND MOLDED AND BONDED TO BOTH SAID LOOP AND SAID END PORTION,SAID CONNECTION INCLUDING TWO SUBSTANTIALLY DIAMETRICALLY OPPOSITELOADING PORTIONS SPACED BY APERTURES DEFINING VOIDS, THE SAID ROD HAVINGSAID LOOP EXTENDING ALONG THE DIAMETRIC AXIS OF SAID LOADING PORTIONS,WHEREBY SAID ROD MEANS CAN ROTATE ABOUT SAID JOINT AGAINST RELATIVELYLIGHT FORCE IN THE ELASTOMER DUE TO SAID VOIDS, SAID ROD MEANS BEINGRESTRAINED BY SAID LOADING PORTIONS FROM TRANSLATION OF THE TWO RODMEANS RELATIVE TO EACH OTHER BY CONSIDERABLY GREATER ELASTOMERIC FORCE,WHREBY A LONGITUDINAL FORCE ALONG THE AXIS OF THE SAID ROD MEANS HAVINGSAID LOOP, TENDS TO PRODUCE TENSION IN SAID ELASTOMERIC CONNECTING MEANSON ONE SIDE OF SAID END PORTION AND COMPRESSION IN SAID CONNECTING MEANSON THE OTHER SIDE OF EACH END PORTION AND TRANSLATION OF SUCH STEERINGJOINT, WHICH IN TURN ACT TO CAUSE RELATIVE ROTATION OF THE OTHER SAIDROD MEANS IN A PLANE APPROXIMATELY PARALLEL TO THAT OF THE FIRST NAMEDROD MEANS WITH RESULTANT ROTATION OF SAID END PORTION RELATIVE TO THEAXIS OF SAID LOOP, WHEREBY TORSION IS SET UP IN SAID ELASTOMERICCONNECTING MEANS ALONG THE PLANE OF SAID LOOP, THE LEVEL OF TORSIONALFORCE BEING A FRACTION OF WHAT WOULD BE PRESENT IN A SOLID SAIDELASTOMERIC CONNECTING MEANS BECAUSE OF SAID VOIDS.